WhisperPhone Duet is an acoustical telephone that enhances student-to-student and teacher-to-student reading activities. Duet keeps classrooms quieter by creating an acoustically-clear connection between two readers. Duet also helps develop reading skills and encourages expressive reading teachers want. WhisperPhone Duet comes with 2 handsets linked by an expandable (up to 6 feet) voice tube. Dishwasher safe.